Flesh foods and the preservation thereof



Patented Mar. 28,1939

FLESH FOODS 'AND THE PRESERVATION THEREOF Carl A. Hedreen, Seattle,Wash., and Harry It.

Beard, Vancouver, British Columbia, Canada, assignors to New EnglandFish Company, Seattle, Wash., a corporation of Maine No Drawing.Application June 11, 1934,

Serial No. 730,150

11 Claims.

This invention relates to flesh food articles and the preservationthereof; and is particularly concerned with a novel type of treatedarticle and with new and beneficial methods and materials for treatingand preserving perishable articles of food, to produce such improvedarticle.

In general, the invention contemplates improvements in the freezing,handling, storage,

. and shipment of perishable foodstuffs or comesti- I bles; improvementsin the treating, preserving, or

coating materials utilized in such methods or processes; andimprovements in frozen and/or cold storage foodstuffs produced by suchmethods. While the invention is of general adaptability in this field,it is especially adaptable and useful to. the preservation of fishor-other seafoods, and the like, which are very susceptible to damage,rapiddeterioration, impairment of quality, flavor, appearance, andresultant reduction in marketability. Similarly, although certainaspects of the invention are of general utility in connection with thevarious steps of freezing, handling, and storing, of foodstufis (asabove set forth), the invention is in general of peculiar importance andadvantage in connection with the coating or glazing of fish, and thelike, at an intermediate stage between the steps of freezing and storingthe fish. Therefore, the method of the invention will be hereinafterdescribed, for

the most part, with reference to its utilization as an intermediate stepof a fish freezing process proper and a subsequent storing of the frozenfish.

More specifically, this invention relates especially to improvements inglazes, or similar coatings, for foodstuffs, improved glazing solutions,improved methods of carrying out the glazing,

and improved articles finally produced. The objects, nature, advantages,and practice, lof the invention will be more clearly understood after.

a brief discussion of certain prior art practices.

In the known art of freezing, treating and preserving fish and otherfoodstuffs, various being set forth somewhat more fully in a briefanalysis of the prior art appearing in the preliminary part of thespecification of Harry R. Beards United States application No. 354,445,filed April 11, 1929, which issued on June 26, 1934, as Patent No.1,963,965 (and in the corresponding Beard,

Canadian Patent No. 329,213, issued January 10, 1933).

Another practice now known in the art, involving the freezing andstoring of foodstuffs (but particularly useful in freezing thereof) isdis- 5 closed and claimed in the aforesaid case of H. R. Beard whichembodies certain improvements over the earlier art. Briefly, that caseinvolves the treatment offish and the like by an extremely high-speedcurrent of some refrigerated gaseous 10 medium, with certain humidifyingand other features, in order to minimize autolysis or self-digestion,and other impairment of the goods or objects being treated. 7

Still another practice now known in the art is 15 disclosed and claimedin H. R. Beards United States application 354,446, filed April 11, 1929,which issued on August 14, 1934, asPatent No. 1,969,832 (and in acorresponding Canadian Patent No. 329,214, granted January 10, 1933)which 20 may be briefly described as involving the application of awater-ice glaze to the articles, during the freezing process proper, tominimize desiccation, and the like.

Further developments of the art, both with re- 25 gard to freezing, andglazing, for storage, are disclosed and claimed in H. R. Beards United rStates application No. 426,206, filed February 6, 1930, which issued onAugust 14, 1934, as Patent No. 1,969,833 (and in a correspondingCanadian 30 Patent No. 332,293, issued May 9, 1933), and involve,briefly, a continuous system for freezing, glazing, andhandlingfoodstufls, an apparatus being therein disclosed which iscapable of use in connection with some of the practices hereinbe- 35fore mentioned.

While the details of such prior developments need not be set forth here,since reference may be made to descriptive matter contained in theaforementioned patents, it should now be pointed out that the presentinvention fundamentally contemplates substantial improvement in theglazing solutions and methods, the glaze produced, and the resultanttreated and stored article, as compared with the results effected bysuch 45 prior methods either when employed singly or in variouscombinations; and the present invention is especially useful whenemployed immediately following the aforesaid Beard freezing processes,or other,known freezing methods. 5

A major diffic'ulty heretofore encountered, especially immediatelyfollowing the freezing proper, and prior to sending the articles out forshipment, or into cold storage, has been the cracking, chipping, orgeneral damaging of the finished 55 glaze, especially immediatelyfollowing a very low temperature freezing process.

Whether the fish have been frozen without a glaze, by any of the knownmethods, and then glazed for storage or shipment; or whether they havebeen glazed as a part of the freezing process proper; if they are takenfrom the freezer at a temperature of around F. or lower, and thenglazed, or reglazed, for storage or shipment, severe cracking, chippingand/or other damaging of the glaze frequently occurs. To obtain anexcellent, impervious and thick, iceglaze over the entire surface ofeach article, immediately after freezing and just prior to placing thearticle in storage, has been a peculiarly difficult problem, of adouble-headed nature, for, on the one hand, the lower the temperature ofthe fish when dipped in the glazing water the worse has been thecracking of the glaze immediately upon removal of the fish from thewater, while, on the other hand, the higher the temperature of the fishwhen dipped in the water, the thinner has been the resultant glaze,which also takes more time to form, under those conditions. This hasbeen the crux of the difficulty, in applying glazing to foodstuffs,after freezing, preliminary to placing them in cold storage,

To elaborate a little on the foregoing, if fish are taken from a sharpfreezer at F. or lower, or from some freezing system such as describedin the above-mentioned patents at perhaps minus 30, minus 40 or evenminus 5t)", and then contacted with water at about plus 34 F., as byspraying or dipping them in a bath of water, the glaze or coating of icefrequently cracks or chips badly, shortly after removal from the glazingbath, and in some instances pieces of the ice film may actually breakloose from the surface and leave a patchy glaze, and thus perhapsnecessitate a reglazing. The importance of a heavy, impervious glaze canhardly be overemphasized, since such a coating (especially as appliedjust prior to storage or shipment) is intended to protect the surfacetissues of the fish.

from loss of water by evaporative processes and thus to prevent themfrom taking on a shrunken and whitened appearance; to avoid oxidationchanges, such as darkening and discoloration of blood, yellowing offlesh and skin, and rusting of, and development of rancidity in, oilsand fats of the fish, due to the atmosphere being in direct contact withthe tissues,

As long as the glaze lasts, excellent protection is afforded, evenduring many months of storage, because the fish tissues themselvescannot lose water until after the glaze has evaporated, nor can theoxygen of the air come into direct contact with the fish. Upon damage tothe glaze, or evaporative loss of the glaze if it is too thin (whichnecessitates reglazing during the storage period), drying and oxidativechanges take place and the surfaces of the articles become damaged tosuch an extent that they must be trimmed oif. If the damage is slight,there is a partial loss not only in weight but in grade; and if thedamage is extensive a total loss may result, and the monetary losses dueto these undesirable changes are very large. It is an expensiveprocedure to remove the fish from the storage piles or racks, atsuitable intervals, to reglaze them, and even in the best managed coldstorage plants this is not apt to be done as fre quently as is reallydesirable.

Another point of importance which should not be overlooked is thedesirability of having a glaze which is not only free from cracks andblemishes but also clearly transparent, and preferably colorless, notonly to make the product appear at its best, but to enable a criticalinspection of the fish itself to be made. Buyers judge quality of frozenfish by the color of the cut surfaces, color of skin, quantity of scaleson the fish, presence of yellowing, fading, and other undesirablevisible signs; and it will readily be seen that the presence of manycracks in the glaze prevents careful inspection and detracts from thegeneral appearance of the product in much the same manner as a crackedshow window interferes with inspection of goods on display.

To place a plain water-ice-glaze on frozen fish, just prior to puttingthem in storage it has been general practice, where fish have beenfrozen at extremely low temperatures (such as minus 5 F. to minus 45 F.)to take the fish and pile them in the glazing room, where thetemperature is considerably higher (usually plus F. to around F. ormore) and to let the temperature of the fish rise, substantiallythroughout, up to approximately the temperature of the g1aZ- ing room,before they are dipped in the bath. This has to a considerable extentminimized the cracking of the glaze immediately after the dipping andprior to storage; but not only does such a procedure necessitateextensive extra handling, with bruising and breaking of tails and finsof the fish, but a considerably thinner glaze has thereby been obtainedthan would have resulted had the fish been glazed while they were attheir lower temperature, immediately upon leaving the freezer; so thatrepeated glazings during storage have been necessary, heretofore.

In addition, when fish are at substantially the temperature of theglazing room, when glazed, softening of the thin portions (such as thebelly walls of headed and gutted fish) takes place by the time a goodcoating is applied to the thicker portions; and such softened parts bendwhen the fish are being handled immediately after the glazing process,with consequent peeling of the glaze, which is often as detrimental asthe cracking which results when the fish are glazed at very lowtemperatures. On the other hand, when the fish are taken immediatelyfrom the freezer, at very low temperature, and glazed before they comeup materially from that temperature, there is a great difference in thethickness of the glaze obtained on different portions of the fish, withresultant irregular evaporation of the glaze during storage, in additionto the undesirable cracking heretofore discussed.

The present invention, in overcoming the foregoing difficulties,involves specifically a glazing bath having a slightly lower freezingpoint than plain water, which comprises a solution, consisting of one ormore substances, dissolved in water, harmless from a food standpoint andwhich do not react with the fish in such a way as to cause anyundesirable change, and preferably also of such a nature as to give arelatively clear glaze of a somewhat flexible or yielding character ascompared with a plain ice-glaze. It has been found that a wide varietyof substances, and thus of solutions, for the glazing bath, may beemployed, and that a very excellent, clear, thick,relatively-non-peeling and non-cracking glaze, of a more uniform naturemay be obtained even though the fish, when placed in the bath, are atan-extremely low temperature, such, for example, as minus 45 F. Thenature of the film thus formed, and the theory back of it, so far as atfor refrigerated shipment, by a continuous apparatus and process, forexample, such as 'dis-' present understood, will be further discussedherein, after some consideration of the practice of the invention.

For the purposes of the invention it has been found possible to employ,in the glazing bath, any of a numerous variety of chemicals, and ofchemical compounds, (organic and inorganic), including, for example,elements, compounds. or derivatives, in one form or another, of avariety of types, such as: chlorides; sulphates; carbonates; phosphates;these combined with sodium or other positive radicals; carbohydrates; etcetera.

As specific examples, of some of 'the foregoing which have been testedand found suitable, may be mentioned the following sugars and salts,most of which are readily and cheaply available: I

Sucrose (cane, beet or other ordinary sugars), dextrose (glucose and thelike), sodium chloride, sodium carbonate, sodium acid carbonate,disodium phosphate, tri-sodium phosphate, sodium acid phosphate, andsodium sulphate.

A moderate amount of one or more other elements and/or impurities,present in the prepared solution, so long as they be not of a harmfulnature, does not appear to be materially detrimental to the ultimateglaze.

Sucrose and sodium chloride, particularly the latter, have been found tobe especially good, in giving a clear, tough, yieldable, non-crackingglaze, at low cost.

The concentration of the substances dissolved in the glazing waterdepends primarily upon the temperature of the fish which are to beglazed, the colder the fish the greater the concentration; but in anyevent the concentration need not be very high, and with fish at usualtemperatures in the sub-zero range, as they leave the freezer, theconcentration of the material added to the glazing water probably neednot, even in extreme cases, be more than around 1 or 2%. In fact, it hasbeen found that, with the average temperature of frozen fish, the bestconcentration is between of 1% and A3 of 1%, and preferably about A; of1% to about A; of 1%, by weight, of the particular material chosen to beadded to the water. It seems to be desirable not to give a heavierconcentration than necessary to prevent cracking of the glaze, asotherwise the glaze may become somewhat mushy, under shippingconditions, where the fish warm up toabout 20 to 30 F.

A very convenient way of practicing the invention might now beexplained, as follows:

The fish are first frozen, by any ofthe known methods (a. few of whichare briefly indicated hereinabove) for example by ahigh-speedlowtemperature current-of some gaseous medium, such as air,carbon dioxide gas, or other substance which is harmless to the fish.The latter method is in accordance with the first of the Beardapplications above mentioned, and attains a high quality in the frozenfish itself. Ordinary sharp freezers are alsosatisfactory.

During thefreezing proper, particularly at an early stage thereof (andsuccessively at different stages, if desired) any desired knownprotection may be afio'rded to the fish as against desiccation by thefreezing medium. In some cases it is preferable to employ a glaze, whichmay be of the type involved in the present invention, or desirably ofthe plain water-ice type applied as described in the second of the saidBeard applications.

Preferably also, the fish are handled through the freezing process anddelivered into storage, or

closed in the third-mentioned Beard application, in which the fish areloaded onto endless conveyors, transported into a cold air streamfreezing tunnel, moved into a glazing chamber for dipping or sprayingwith water, moved back into the freezing tunnel where sufii'cienttraverse is made to complete the freezing, moved out of the freezingtunnel to a point where the conveyor may be slightly warmed for ease ofremoval of the fish, and finally, unloaded from the conveyor system andtransported into storage.

By such an arrangement of method and apparatus, the fish normally comefrom the freezer at very low temperatures, for example, minus 20 F. orminus 30 F., although the range may extend to a few degrees above zero,or in the other direction down to minus 50 F. or lower. The fish comefrom such a freezing system in very excellent condition, and inaccordance with present practice are usually then placed in cold storageat around +'l0 to +20 F. or higher, although this storage range may alsoextend downwardly to around 0 F. or a few degrees lower.

Intermediate the freezing and placing of the fish in storage, thepresent invention contemplates dipping the fish in a glazing solution orbath, of the nature hereinbefore specified, before the fish have losttheir reserve refrigeration, and preferably while they are still at asub-zero temperature. The fish take up heat from the film of water indirect contact with them, until an I encasement or film of substantiallynon-cracking glaze is formed on all the exposed surfaces. The thickeningof this glaze ceases when the temperature of the surface layers of thefish approaches the freezing point of the solution, and the fish arethen removed from the bath, so that the coating already formed does notcommence to thaw.

The glazing bath may desirably be at about 34 F. and the colder the fishare when they are dipped in thisbath the thicker will be the glaze onthe surface. With certain articles of food which are readily wrapped orpacked, the encasement may include any desired pack-aging, followed bythe glazing.

By the above described method, particularly when employed in thespecific series of steps just recited, all the advantages and desirablecharacteristics of the quickly frozen fish are retained, the fish neednot be warmed up to the temperature of the glazing room (as washeretofore the usual practice in order to prevent cracking of theglaze), and upon.moving them from the glazing into the storage stagethere is little damage to the glaze due to handling of the fishflesshandling is necessary, the frequency of repeated glazings during storage.is reduced and in general the-quality of the goods is maintained and ata lower. cost than hertofore required; f

Theoretically, the reasons for the necessity, heretofore, of warming upthe fish prior to glazing for storage, where plain water was used astheglazing medium, appear to be as follows:

In the first place, if a very cold fish is dipped in the glazing baththe ice film formed seems to be more brittle because of the lowertemperature. When such fish are first removed from such a plain waterbath, no cracking takes place but in a few seconds to a few minutesafterwards the cracking does take place. Very probably there areexpansions and contractions in the fish itself during the temperaturechanges that take place in it after it is removed from the glazingwater,

and the resultant changes in volume apparently induce the cracking ofthe brittle glaze, as does also the sudden cooling of the ice film fromthe under side next to the fish, which takes place very quickly afterthe fish are removed from the glazing water. The nature and rapidity ofthe cracking of the glaze, under such circumstances, seem similar to thecracking of hot glass when it is cooled suddenly.

With the improved glazing solution of the present invention, apparentlythe crystalline or other structure of the glaze is modified, as well asthe chemical composition, in a way to produce a more flexible frozenfilm. Whatever be the theory, the fact is that the addition of what maybe termed the modifier, of the present invention, to the glazing bathproduces a resultant glaze which is thick, tough, clear, and highlyresistant to fracture, damage or cracking, either by impact ortemperature change. If fish, when so glazed, are pounded together orthrown on the floor, only a small spot of pulverized ice forms,immediately at the point where the impact took place, and with nonoticeable radial cracks.

Furthermore, the glaze of the present invention appears to be of verysimilar or identical composition to that of the solution itself, becausethe fish are at such a low temperature, and freezing takes place sorapidly, that separation of the modifier from the water does not occur.

What is claimed is:

1. As a new article, a frozen flesh food in an encasement comprising atough, adherent, substantially air-tight ice-glaze coating having alower freezing-point and substantially greater resistance to cracking,peeling and fracture than pure water-ice and formed of a frozen solutionof water and an edible non-injurioussolute characterized by its abilityto so reduce the freezingpoint and increase the toughness of the glaze.

As a new article, a frozen fiesh food in an encasement comprising atough, adherent, substantially air-tight ice-glaze coating having alower freezing-point and substantially greater resistance to cracking,peeling and fracture than pure water-ice and formed of a frozen solutionof water about 98% to 99.9% and the balance an edible non-injurioussolute characterized by its ability to so reduce the freezing-point andincrease the toughness of the glaze.

3. As a new article, a frozen flesh food in an encasement comprising atough, adherent, substantially air-tight ice-glaze coating having alower freezing-point and substantially greater resistance to cracking,peeling and fracture than pure water-ice and formed of a frozen solutionof water about 98% to 99.9% and the balance an edible non-injurioussolute characterized by its ability to so reduce the frezing-point andincrease the toughness of the glaze, said solute consisting of at leastone material of the following'group: sucrose, dextrose, sodium chloride,sodium carbonate, sodium acid carbonate, di-sodium phosphate, tri-sodiumphosphate, sodium acid "phosphate and sodium sulphate.

4. In the preservation of flesh food articles involving freezing andsubsequent refrigerated storage or shipment, the method which comprisesrefrigerating the articles to a temperature within the sub-zero range,and, before the aveage temperature of the articles can rise appreciablyabove 0 F., glazing the articles under the influence of their ownrefrigeration by subjecting them to an aqueous glazing bath of a highertemperature and incorporating, in solution, material from the class ofedible water-soluble materials non-injurious to said articles andadapted to lower the freezing point of the solution, and regulating theconcentration of the solution to maintain the solute therein in amountsat least .1% by weight when the articles being glazed have a temperaturein the vicinity of 0 F. and at greater concentrations when the articlesare at substantially lower temperatures, thereby rendering the resultantglaze tenacious and highly resistant to cracking and like damage, butlimiting the maximum concentration to less than that which would producemushiness of the glaze at normal cold storage or shipping temperaturesabove the original refrigerating temperature.

5. In the preservation of flesh food articles involving freezing andsubsequent refrigerated storage or shipment, the method which comprisesrefrigerating the articles to a temperature within the sub-zero range,and, before the average temperature of the articles can rise appreciablyabove 0 F., glazing the articles under the influence of their ownrefrigeration, in such manner that the applied glaze is of substantiallythe same composition as the bath from which it was formed, by subjectingthem to an aqueous glazing bath of a higher temperature andincorporating, in solution, material from the class of ediblewatersoluble materials non-injurious to said articles and adapted tolower the freezing point of the solution, and regulating theconcentration of the solution to maintain the solute therein in amountsat least .1% by weight when the articles being glazed have a temperaturein the vicinity of 0 F. and at greater concentrations when the articlesare at substantially lower temperatures, thereby rendering the resultantglaze tenacious and highly resistant to cracking and like damage, butlimiting the maximum concentration to less than that which would producemushiness of the glaze at normal cold storage or shipping temperaturesabove the original refrigerating temperature.

6. In the preservation of flesh food articles involving freezing andsubsequent refrigerated storage or shipment, the method which comprisesrefrigerating the articles to a temperature within the sub-zero range,and, before the average temperature of the articles can rise appreciablyabove 0 F., glazing the articles under the influence of their ownrefrigeration by subjecting them to an aqueous glazing bath of a highertemperature and incorporating, in solution. material from the class ofedible water-soluble materials non-injurious to said articles andadapted to lower the freezing point of the solution, regulating theconcentration of the solution to maintain the solute therein in amountsat least .1% by weight when the articles being glazed have a temperaturein the vicinity of 0 F. and at greater concentrations when the articlesare at substantially lower temperatures, thereby rendering the resultantglaze tenacious and highly resistant to cracking and like damage,butlimiting the maximum concentration to less than that which wouldproduce mushiness of the glaze at normal cold storage or shippingtemperatures above the original refrigerating temperature, andcompleting the formation of the glaze on said articles with suchrapiditythat the glaze is of substantially the same composition as thesolution from which it was formed.

'7. In the preservation of flesh food articles, the method whichcomprises refrigerating the articles to a temperature within thesub-zero range, and

thereafter, before the average temperature of the articles can riseappreciably above F., contacting .the articles with a glazing solutioncomprising water 99.9% to about 98% and an edible solute characterizedby its ability to lower the freezing point of the solution and to renderthe resultant glaze highly resistant to cracking and like damage, saidsolute being by weight .1%

to about 2%.

8. In the preservation of flesh foods, the meth od which comprisesrefrigerating the articles to a temperature within the sub-zero range,and, before the average temperature of the articles can rise appreciablyabove 0 F., glazing the articles by subjecting them to an aqueousglazing solution comprising an edible solute characterized by itsability to lower the freezing point of the solution and to render theresultant glaze tenacious and highly resistant to cracking and likedamage, said solute consisting of at least one material of the followinggroup: sucrose, dex

can rise appreciably above 0 F., glazing the articles by subjecting themto a glazing solution comprising water 99.9% to about 98% and an ediblesolute characterized by its ability to lower the freezing point of thesolution'and to render the resultant glaze tenacious and highlyresistant to cracking and like damage, said solute being by weight .1%to about 2% and composed of at least 'one material of the'followinggroup: sucrose,

dextrose, sodium chloride, sodium carbonate, sodium acid carbonate,di-sodium phosphate, trisodium phosphate, sodium acid phosphate andsodium sulphate.

10. The method of preserving comestibles, such as fish and likearticles, which includes freezing the articles to a temperature lying ina range between about +5 F. and -50 F., and while so frozen applying tothe articles a protective ice-glaze containing a fraction to 1% ofsodiumchloride.

11. The method of preserving comestibles, such as fish and likearticles, which includes freezing the articles to a temperature lying ina range between about +5 F. and 50 F., and while so frozen applying tothe articles a protective ice-glaze containing a fraction to 1% ofsucrose.

CARL A. HEDREEN. HARRY R. BEARD.

